4,195,193 research outputs found
Black hole entropy in scalar-tensor and f(R) gravity: an overview
A short overview of black hole entropy in alternative gravitational theories
is presented. Motivated by the recent attempts to explain the cosmic
acceleration without dark energy, we focus on metric and Palatini f(R) gravity
and on scalar-tensor theories.Comment: 24 pages, latex, to appear in "Entropy in Quantum Gravity", special
issue of Entropy, R. Garattini editor
Time-Resolved Two-Photon Quantum Interference
The interference of two independent single-photon pulses impinging on a beam
splitter is analysed in a generalised time-resolved manner. Different aspects
of the phenomenon are elaborated using different representations of the
single-photon wave packets, like the decomposition into single-frequency field
modes or spatio-temporal modes matching the photonic wave packets. Both
representations lead to equivalent results, and a photon-by-photon analysis
reveals that the quantum-mechanical two-photon interference can be interpreted
as a classical one-photon interference once a first photon is detected. A novel
time-dependent quantum-beat effect is predicted if the interfering photons have
different frequencies. The calculation also reveals that full two-photon fringe
visibility can be achieved under almost any circumstances by applying a
temporal filter to the signal.Comment: 6 pages, 4 figure
Native Impact Prologue
This document is a prologue for the Native Impact project. It is written by Dr. Henry Hank Lehrer, and provides his insights on the beginnings of a decade-long educational journey
Curriculum Vitae - Dr. Henry Hank Robert Lehrer
Curriculum Vitae - Dr. Henry Hank Lehrer
An overview of New England's economic performance in 2008
Like most of the nation, New England suffered economically in 2008. Job losses, rising unemployment, and slumping real estate markets were all factors in one of the worst years for the region’s economy. Nevertheless, while the recession certainly took its toll, it did not affect New England as much as it did the nation as a whole.Economic conditions - New England
Light Meson Dynamics Workshop. Mini proceedings
The mini-proceedings of the Light Meson Dynamics Workshop held in Mainz from
February 10th to 12th, 2014, are presented. The web page of the conference,
which contains all talks, can be found at
https://indico.cern.ch/event/287442/overview .Comment: 46 pages, 17 contributions. Editors: W. Gradl, P. Masjuan, M.
Ostrick, and S. Schere
An overview of New England's economic performance in 2007
New England’s economy showed bright signs of growth in 2007, but residential real estate cast a shadow. Job growth was moderate and on par with that of the nation, but the region fared better with an unemployment rate lower than the national average. Exports from the region rose in value, but at a lesser pace than seen in the nation. Although the region remained the richest in per capita income, growth in total personal income in New England was slower than in the nation. Declining home prices, a significant reduction in housing permits, and spikes in foreclosures rounded out a generally dismal real estate picture. But no matter how dreary, the overall picture for New England may be a little brighter than that for the nation.Economic conditions - New England
Overview of ASDEX Upgrade results
The ASDEX Upgrade (AUG) programme is directed towards physics input to critical elements of the ITER design and the preparation of ITER operation, as well as addressing physics issues for a future DEMO design. Since 2015, AUG is equipped with a new pair of 3-strap ICRF antennas, which were designed for a reduction of tungsten release during ICRF operation. As predicted, a factor two reduction on the ICRF-induced W plasma content could be achieved by the reduction of the sheath voltage at the antenna limiters via the compensation of the image currents of the central and side straps in the antenna frame. There are two main operational scenario lines in AUG. Experiments with low collisionality, which comprise current drive, ELM mitigation/suppression and fast ion physics, are mainly done with freshly boronized walls to reduce the tungsten influx at these high edge temperature conditions. Full ELM suppression and non-inductive operation up to a plasma current of Ip = 0.8 MA could be obtained at low plasma density. Plasma exhaust is studied under conditions of high neutral divertor pressure and separatrix electron density, where a fresh boronization is not required. Substantial progress could be achieved for the understanding of the confinement degradation by strong D puffing and the improvement with nitrogen or carbon seeding. Inward/outward shifts of the electron density profile relative to the temperature profile effect the edge stability via the pressure profile changes and lead to improved/decreased pedestal performance. Seeding and D gas puffing are found to effect the core fueling via changes in a region of high density on the high field side (HFSHD). The integration of all above mentioned operational scenarios will be feasible and naturally obtained in a large device where the edge is more opaque for neutrals and higher plasma temperatures provide a lower collisionality. The combination of exhaust control with pellet fueling has been successfully demonstrated. High divertor enrichment values of nitrogen En > 10 have been obtained during pellet injection, which is a prerequisite for the simultaneous achievement of good core plasma purity and high divertor radiation levels. Impurity accumulation observed in the all-metal AUG device caused by the strong neoclassical inward transport of tungsten in the pedestal is expected to be relieved by the higher neoclassical temperature screening in larger devices.This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018
under grant agreement number 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.Peer ReviewedPostprint (published version
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